Metalation, especially lithiation, of polyolefin halides, such as polyvinyl chloride and polyvinyl bromide, is known to yield useful intermediates. These intermediates can be used to produce functionalized polyolefin halides and graft and cross-linked copolymers containing a polyolefin halide.
A process for producing these intermediates is reported in "Reaction of n-Butyl-lithium with Poly(vinyl Chloride)", K. Shina et al, Journal of Polymer Science: Part A-1, Vol. 4, 1069-1079 (1966). The process comprises adding n-butyl lithium in n-heptane to a stirred anhydrous tetrahydrofuran/poly-vinyl chloride solution, which solution is initially at room temperature. The reaction mix is reported to take on a deep purple color indicating that lithiation, to some degree, of the polyvinyl chloride has occurred. Hydrolysis, carbonation, etc, or the addition of styrene or other polymers for grafting to the reaction mix were effected after the lithiation reaction. It is reported that all resultant polymers, except grafted styrene, were yellow or pale yellow, brittle substances which were insoluble in benzene, alcohol, cyclohexane, carbon tetrachloride, and the like. These properties foretell of little commercial acceptability for these polymers and are an indication that the metalation reaction is producing a moderately highly cross-linked intermediate.
Therefore, it is an object of this invention to provide a process for metalation of polyolefin halides to produce an intermediate which yields a graft copolymer or a functionalized polyolefin halide product which has a white or very pale color, pliability and exhibits good solubility in most solvents.